diff --git a/as/thrift.js b/as/thrift.js
index 752bab724..5ab1803f7 100644
--- a/as/thrift.js
+++ b/as/thrift.js
@@ -53,6 +53,7 @@ function TChannelAsThrift(opts) {
         allowFilesystemAccess: true,
         allowIncludeAlias: opts.allowIncludeAlias,
         allowOptionalArguments: opts.allowOptionalArguments,
+        defaultAsUndefined: opts.defaultAsUndefined,
         fs: opts.fs
     });
 
diff --git a/package.json b/package.json
index 89a39f3c7..b0f0dea95 100644
--- a/package.json
+++ b/package.json
@@ -45,7 +45,7 @@
     "safe-json-parse": "^4.0.0",
     "sse4_crc32": "4.1.1",
     "tape-cluster": "2.1.0",
-    "thriftrw": "^3.8.0",
+    "thriftrw": "^3.10.0",
     "xorshift": "^0.2.0",
     "xtend": "^4.0.0"
   },